Mystery twin
by GravityFallsgirl22
Summary: It's about Mainly Dipper and Mabel finding out they have another twin. If anyone has any ideas on it, PM me or leave it in your review, Thanks. Oh and also i've rated it T just to be on the safe side as not sure what to do for some chapters. If you want to read just one of my stories I would recommend the other two as they are more resent and better then this one.
1. Chapter 1

12.00- Midnight

It was a cool calm night, and the moon was casting creepy shadows outside the mystery shack. Mabel and Dipper were fast asleep. Dipper had his book over his head and was snoring rather loudly and Mabel had dozing Waddles on her lap. A small, strange light was shining through the bedroom window and there was a knocking at the door. Dipper woke frantically.

"Mabel…Mabel…WAKE UP!" Dipper shouted

"What do you want…can't you see I'm trying to sleep!" Mabel sleepily spoke

"Look a weird light shining through the window and if you listen closely, there is a faint knocking at the door" Dipper whispered

Mabel hesitated and listened "so there is… lets go investigate…mystery twins?"

"Mystery twins" Dipper agreed

They both whipped on the dressing gowns and tiptoed down the corridor and then down the stairs, being extra carful when walking past Grunkle Stan's room as he was snoring really loudly. They reached the gift shop and were just about to open the door when…

"Oh no" Mabel said

"What?" Dipper interrupted

"I left professor Waddles up stairs…" Mabel began

"Look Mabel now's not the time. We may have a mystery on our hands and all your bothering about is Waddles" Dipper interrupted

"Ohhh ok" Mabel said, sticking her tongue out at Dipper

Dipper retaliated, sticking his tongue out at Mabel. He then carefully opened the door to find…

**That's all for my first chapter sorry is it's really short it's my first EVER chapter. Hoped you like it and please leave reviews :)**


	2. Chapter 2

To find…

… A girl. She was wearing a scruffy torn jumper and a muddy skirt. She had long brown hair, like Mabel's, and brown eyes. She looked about 12. She had a small bag with clothes bursting out.

"Hi" She said, "Can I stay with you please?"

"Of course you can" Mabel said Joyfully

"Hey Mabel" Dipper whispered pulling her over to the counter "Don't you think she looks a little strange?"

"No why, She's just a girl looking for somewhere to stay, that's all." Mabel replied.

Mabel walked back to the door. "Sorry about my '_little' _Bro, sure you can come in. You can stay with me" Mabel said exaggerating the _'little' _so not to forget the 5 minute difference between her and Dipper.

The girl walked in and the 3 of the tip toed back to their bedroom and within minutes were fast asleep.

8.00am 

Dipper awoke to find Mabel and the girl playing with Waddles.

"Look at him Prim, He's soooo cute as a police man…" Mabel said

"Whoa, Whoa, Wait, Prim?"

"Yep that's me," the strange girl said

Dipper stared at Prim for a little while and then shook his head.

"What is it Bro?" Mabel said curiously

"Well… it's…umm…nothing Mabel" Dipper replied, struggling.

"Tell me" Mabel said

"It doesn't matter Mabel" Dipper replied

"TELL MEE" Mabel screamed

"Ok, Ok, calm down, It's just you and prim you look alike and I'm sure I recognize prim from somewhere that's all" Dipper said

"Funny that" Mabel said "Me to"

**That's it for chapter 2, sorry the chapter's are short I plan to make them longer soon. Please review :)**


	3. Chapter 3

"Funny that" Mabel said "Me too"

Dipper in his flashback

It was early morning and baby Dipper and Mabel were in their cots. There is another cot with another young girl. Their mother walks in.

"Good morning my little baby's" Mum said

She walked over to the other cot.

"Hello Prim, my 3rd and youngest" Mum said

"googaa" Prim said in baby talk

There was a knocking at the door and mum left the room to answer it. A man. Quite tall entered the room.

"We are having to take your youngest baby away madam" He said

"What… no why?" Mum asked

"Your not able to look after 3, family services said" The man replied.

"Ok…" Mum said

She walked back in "Goodbye my little Prim Pines" She whispered as she picked her up and handed her over to the man.

"Dippy…Dippy…DIPPY!" Mabel said

Flashback Finished 

"Dippy…Dippy…DIPPY" Mabel screamed

"...What" Dipper said

"Oh were you having a flash back?" Mabel asked

"Yes" Dipper replied "And prim is our sister… TWIN sister"

Prim was drinking. As Dipper said that she sprayed out the water all over poor Waddles whom Oinked and left the room.

"WHAT!" Prim squealed

"Yes you heard me right TWIN sister" Dipper said

"OMG!" Prim and Mabel squeaked together

8:30am breakfast

Dipper Mabel and Prim were sitting down at the table eating fruit loops when Grunkle Stan walked in holding his head in agony. He noticed Prim.

"Oh god you two don't do this to me. Now I'm seeing 3 of you!" He said stumbling

"No Grunkle Stan… there is 3 of us" Dipper corrected

"Then who's the third" Stan said

"This, Grunkle Stan, is our other twin PRIM!" Mabel said

"WHAT! You mean there are 3 of you! Oh great! Another to look after!" Stan replied, "Well I suppose on the other hand there is an extra helping out with the mystery Shack…"

"GRUNKLE STAN!" Dipper and Mabel Screamed

"Ok, ok" He replied as he walked out the room, fed up with talking to them.

"So what do you want to do first Mabel?" Dipper said

"hmmm ok, Prim who have you been living with?" Mabel asked curiously

"Well…" Prim started "I lived in a huge great house with a boy aged 9. He had tall white hair and…"

"WHAT!" Mabel screeched "You lived with Gideon?"

"Yes, how did you know that?" Prim asked

"Long story, cut short…HAHA get it Dipper Short, Gideon's short! HAHAHAHA!" Mabel giggled

"Nice one Mabel" Dipper laughed

"MABEL" Prim shouted

"Ok, Ok, I went out with him for a bit" Mabel shivered "Creepy fellow he is, anyway Prim carry on"

"Oh so that's who he kept going on about, MABEL PINES, MABEL PINES." Prim mimicked "Anyway, so his weird parents adopted me to be his 'life companion'. They said it would help him to get over, you, Mabel. So, last night I managed to escape from that nasty place. I wandered the forest all night till I found this place and you guys!"

"WOW strange" Dipper said

At that moment they heard a knocking at the door. They all went to get it. Prim opened the door to find…

**So, guys that's it for my next chapter. Hoped you like the twist where I added with Gideon. I'm sure '****_lil ol gravity falls'_**** will because she loves Gideon. That's why I added him in. Please leave reviews. :) :D**


	4. Chapter 4

Prim opened the door to find…

…Gideon!

"You!" Prim cried

"Yes that's right lil ol me!" Gideon replied, "Prim I just knew you would be here, you see when I found you had gone I came straight over, see I knew you were all Triplets…"

"Whoa, wait how did you know?" Mabel interrupted

"Well you see my little Mabel Marshmallow, when my parents adopted Prim they asked if we knew anyone with the surname of Pines. Well I just went ahead and told them bout you all. So they gave us Prim to return to you. But instead I kept her for my own." Gideon replied in his annoying little voice "And now my friends it's time to end your pretty little lives…"

At that moment Stan walks in

"Wow I heard a annoying voice boring my nephew and nieces. So I came out to get rid of you little…hmm… you little…" Stan began

"Oh Mr. Stan how nice of you to join this little talk." Gideon interrupted.

He clicked his fingers twice and 2 tall bodyguards took the four of them into a car. Stan managed to wiggle his way out from the grip of the guard. He then ran into the forest.

"Don't worry bout him" Gideon confronted his guard. "He's useless anyway"

"Don't call Grunkle Stan useless" Mabel said

"Ok my little Mabel Marshmallow anything for you" Gideon teased

9.00am Stan at the police station 

"… He took my two nieces and my nephew away in a large posh car…" Stan began

"I'm sorry Stan but there are no other witnesses we therefore cannot continue with this investigation," Sherriff Blubs said

"Please" Stan begged, he was down on his hands and knees now "Please, Please, Please"

"No now stop bugging us it's probably just a lie anyway" Sherriff Blubs replied

"Well fine then, I'll get them myself!" Stan shouted as he stormed out the room.

9.00am Gideon's house

The bodyguards took Prim, Mabel and Dipper in a small, narrow back passage into Gideon's room while Gideon went in through the house. Gideon's room was quite large and on a small corkboard there were many pictures of Mabel.

"Well, he's not just magic, he sure LOVES Mabel" Dipper said exaggerating loves and Mabel to make her feel uncomfortable.

At that moment Gideon walked in holding a tub of ice cream.

"Ohhh Ice cream" Mabel said

"Does Mabel want ice cream, well to bad. That's what happens when you break someone's heart" Gideon teased Mabel

"I've come to think that you're all just completely worthless and I have no idea why I spared your lives in the first place…" Gideon began "so… now's the time to kill you all. Oh hang on… ok now's the time to kill you Dipper, and of course I would never hurt a hair on my precious Mabel's head…"

There was a load shattering of glass and the two bodyguards fell to the floor, releasing Mabel, Dipper and Prim.

"Not this time" Stan chanted

"What no" Gideon screamed

"Go kids go" Stan confronted the others

Gideon held his amulet and chanted some strange words lifting Grunkle Stan into the air. He then let go letting Stan fall helplessly to the floor.

"HAHAHA once Stan's dead I shall own the mystery shack," Gideon screeched.

The door creaked open and Gideon's dad walked in giving Stan enough time to run.

"What is all that noise Gideon?" His dad said

"NOOO DAD GET OUT" Gideon screamed, "You ruined my plan" Gideon said through floods of evil tears.

9.30am back at the shack

Stan, Prim, Mabel and Dipper ran into the gift shop and slammed the door behind them. Soos was standing at the counter and Wendy re-arranging gifts.

"Hey guys" Wendy said, "what's up Dip"

"Hey Wendy…ha not much" Dipper said as he walked through the door.

"Oh BYE THEN" Wendy shouted

"Wow what a day" Stan said "And oh come on, you two owe me big time"

"Yeah, we do" Mabel agreed

**That's it. I'm not to sure whether to add any more chapters and what to put in them. So if you want to read more chapters leave it in my reviews, plus I'll need some ideas so yeah. **


	5. Chapter 5

12.00 midnight

Mabel was asleep, but Dipper was wide-awake thinking about what happened earlier on that day. Dipper didn't know but Prim was pretending to be asleep. There was a knocking at the door and when Prim got up to answer it Dipper pretended to be asleep. He then followed Prim downstairs to the gift shop where he managed to sneak behind the counter to listen in. Prim opened the door and Dipper caught a glimpse of Gideon.

"So my little pumpkin how's the acting coming along?" Gideon whispered

"Oh it's coming along fine" Prim replied

"Ok listen in tomorrow night, you let me in and we both go upstairs and kill Mabel and Dipper for revenge!" Gideon said

"Sounds good to me" Prim said

Dipper had heard enough. He snuck back to the bedroom and woke up Mabel.

"What is it" Mabel whispered drearily, clearly she was annoyed

"Prim is working for Gideon, tomorrow night she is going to let Gideon in and kill us both when we are sleeping…" Dipper began

"Look Dipper I know you don't really like Prim, but there's no need to get rid of her, she's lovely" Mabel argued

"Fine then" Dipper said, "Listen to this"

He pulled out his recorder and played the conversation that Prim and Gideon had downstairs.

"Now do you believe me?" Dipper asked

"Yes, now I do… So what's the plan?" Mabel replied

"Ok, Dipper began you hide up here and I distract them in the hallway. Whilst that is happening you set up traps. As I persuade them in here I'll snatch the amulet from Gideon's neck, so he doesn't have any powers" Dipper started "Ok so they walk into the trap, go skidding along the floor and fall into an barrel, then you put the lid on and we kill Prim."

"What about Gideon though?" Mabel questioned

"Um… we'll touchier him just like he did us" Dipper began

Dipper heard footsteps outside the door.

"Quickly back to sleep" He whispered

The door opened and Dipper was in bed just in time. Prim walked in with an evil look on her face. She walked over to Dipper's bed.

"Goodbye Dipper, Mabel to. Mwwwaahaa" Prim laughed evilly.

12.00 midnight, the next night

Prim got up again and went downstairs to let Gideon in.

"Ready Mabel?" Dipper asked

"Ready" Mabel replied

Dipper stepped outside the room and Mabel put oil down on the floor leading to two barrels. She crept into bed and hid the lids under the covers. She then pretended to be asleep.

"Ok Dipper, ready" She whispered

Dipper came back in and lay awake in bed. They heard footsteps approaching the door. Gideon stepped in and next to him Prim. They both stepped forwards and slipped down the oil runway. Dipper snatched the amulet whilst Gideon cursed. Prim and Gideon fell into a barrel each and Mabel stuck the lids on tight. Dipper now knew that Prim was defiantly not their sister and she was forcing Dipper to come up with the flash back. Mabel tied a rope around the barrel Prim was in, and Dipper dragged in outside, screwed on the lid and said that they would dump it in the lake tomorrow. As for Gideon. He was dealt with to. Dipper and Mabel did everything he did to them back.

So this time Mabel and Dipper had a happy ending…

…Or have they?

**Ok, That's it for Chapter 5. I'm not sure if I should do any more chapters. PM or leave whether I should or not in your review. Thanks for reading :) **


	6. Chapter 6

…Or have they?

8.00am breakfast

Mabel and Dipper are sitting at the table eating toast and jam. Grunkle Stan walks in.

"Hey Grunkle Stan" Mabel said

"Hello Mabel, where is Prim?" Stan questioned

"Oh… well it turned out she was just an actor working for Gideon. So we plan to dump the barrel she is in into the lake." Dipper replied

"Oh ok, as long as Gideon leaves you alone" Stan said

They continued to eat breakfast and the went outside to load the barrel into the mystery shack golf cart.

"Wow this is light." Dipper told Mabel

"So it is." Mabel replied helping her brother lift it into the back.

"Ok, so we take it down to the lake throw it in and leave" Dipper confronted Mabel

"Ok, let's go" Mabel answered

They jumped in the front and drove down to Gravity Falls Lake. Mabel rolled the barrel along the jetty and into the lake.

"That's that" Mabel said feeling rather pleased with herself.

8.30am 

They reached the mystery shack and dumped the golf car outside. The two of them then walked in through the gift shop door, where Wendy was talking to Soos.

"Hi guys" Soos said as he waved happily at Mabel and Dipper

"Oh hi Dipper" Wendy began "I was wondering if you wanted to come to the park with me in a second?"

"Yeah sure… but can Mabel come?" Dipper asked

"Yeah" Wendy replied

"Ok well we're just going to go and get ready, see you in a minute" Dipper said

Mabel and Dipper ran up the stairs to their bedroom to see…

**I wasn't too sure whether to add another chapter but thanks to ****_'lil ol gravity falls'_**** I added this one. Another on it's way soon. And like normal don't forget to leave reviews! **


	7. Chapter 7

To see…

… Prim sitting on the bed!

"Hello, Mabel, Dipper" She began

"You… hang on I thought you were in the lake?" Mabel asked

"Oh no, I managed to free myself!" Prim smugly replied "GAURDS!"

Two guards' came out and grabbed both Dipper and Mabel. Prim grabbed her bag and rummaged around to pull out a mobile phone. She dialed a number and someone picked up on the other end. Prim put it on load speaker.

"…Hello?" The voice said

"Hello, Gideon, I have Mabel and Dipper. We are in their bedroom. Come right away." Prim relied

"Mwaahaaaa. That's my girl" Gideon laughed.

Prim hung up the phone and began talking to Mabel and Dipper.

9.00am

Gideon walked in. He had his smart blue suit on and was carrying a knife.

"Well, well my Pine friends…" Gideon began "I've been thinking. You do all this to me I do it back. So who's first? Innocent Mabel or her protective brother Dipper. Hmmm… I say DIPPER"

He plunged the knife into Dippers heart. But alas, Prim had dived in the way just in time. The knife plunged into her stomach.

"What…what…NOOOO" Gideon screamed

"GO." Prim shouted, "I said GO"

"Fine if that's the way you want to play it, so be it. GUARDS!" Gideon shouted, "I'll be back Pines, just you wait and see"

Gideon and the two guards left the room. Trailing down the stairs and out the door.

Prim was on the floor. Mabel ran to her aid, but it was to late.

"Prim, don't go." Mabel whispered

"I have to." Prim replied "Keep this, if ever you need me chant the words"

Prim handed Mabel a tiny piece of paper. Prim had seen her days by, and after that she passed away.

The next day 

Dipper and Mabel had managed to smuggle Prim's body out, they were deep in the woods burying it.

"I'm sorry Mabel, I should have know Prim was going to help" Dipper sobbed

"That's ok, besides we always have each other" Mabel replied "Awkward sibling hug?"

"Awkward sibling hug" Dipper agreed

They lent in the hug.

"Pat, Pat" They said in unison

**So that's the end of my story, hoped you guys liked it. Oh I would like to thank smurphy, my great mate for coming up with this idea. So Thanks.**

**Hoped you all enjoyed. And as always don't forget to review :D :)**


	8. Bonus- From Prim's view

8.00am (Dipper having his flash back)

When Dipper had his flash back I was distracting him from noticing that Gideon was out side using his amulet to control Dipper's flash back.

12.00 midnight (The bit where Dipper and Mabel trap her in the Barrel)

Outside in the barrel it was cold and lonely. So, I decided to escape. I rummaged around in my bag and found the perfect thing to prize open the lid. It took me 2 minutes to work the lid gradually off. When I got out I found the nails and hammer, so I sealed the lid back up. Then I heard Gideon in need of help, although there was nothing I could do. So I waited patiently until he was finally aloud to leave. Then we trudged effortlessly back to Gideon's house. We made a plan and it proceeded the following day.

8.00am (The bit where Dipper and Mabel are downstairs for breakfast)

I launched a grappling hook up through the twins open bedroom window, and then I (and the guards) climbed up the strong, sturdy rope into the bedroom. Then we took our places. Whilst we were waiting for them to come up, I recalled before I had turned on them. They were really kind to me. It changed my opinion of them and Gideon.

8.30am 

So when the twins finally came up and my guards had hold of them, just like our plan I called Gideon…

9.00am

When he came upstairs and into the bedroom, I decided that I had had enough of his cruel ways to Dipper and Mabel so just as he was about to kill Dipper I stepped in and sacrificed my own life for the amazing Dipper (and of course Mabel)

So that's my point of view!

**Ok, this time it's defiantly the end. This was a bonus chapter for those who didn't really understand the plot. Thank you lil ol gravity falls for you awesome ideas and support throughout this story and thank you all for such kind reviews. :)**

**And once again please review! :) **


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